My OnTriggerEnter2D(Collider2D other) not working

Hi there, I have a script which I attached it to my obstacles, and when the player collides with the obstacles, a debug log should print out a message “Player Respawn”. However, my OnTriggerEnter2D in the script is not working and I dont know why. Can someone help me please?

public class KillPlayer : MonoBehaviour {
 
     public LevelManger levelManager;
 
     // Use this for initialization
     void Start ()
     {
         levelManager = FindObjectOfType<LevelManger>();
     }
     
     // Update is called once per frame
     void Update () {
     
     }
 
     void OnTriggerEnter2D(Collider2D other)
     {
         if (other.tag == "Player")
         {
             levelManager.RespawnPlayer();
         }
     }
 }

And below is the script for LevelManger:

 public class LevelManger : MonoBehaviour {
 
     // Use this for initialization
     void Start () {
     
     }
     
     // Update is called once per frame
     void Update () {
     
     }
 
     public void RespawnPlayer()
     {
         Debug.Log("Player Respawn");
     }
 }

And this is my Player:
99394-a.jpg

And this is my obstacle which I attached KillPlayer script to:
99395-b.jpg

Your Player is tagged with “Untagged”, not “Player”.

Also, your levelManager variable has no value set in the inspector, so you’ll get a NullReferenceException once you fixed the tag; unless you drag your LevelManager GameObject into the inspector.